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Discussion Starter #1
I'm getting ready to rebuild the rear drums on my '66. So I ordered a set of replacement drums from NPD for a V8 '66. Drums that I received are what I ordered but they are different than those on the car! In profile, the drums on the car now are "flat across the top". The new ones from NPD have a raised center containing the bolt holes. The shoes are 1 3/4" and all the '66 V8 replacement hardware matches. Anybody got any ideas for the difference in the drums?

I'm going to trial fit the NPD replacements on the car today and see if they fit as a first step. My bet is that they will and then I'll be left trying to figure out if there is a mechanical reason why someone chose not to use the the correct replacement part. Any thoughts?

It has occurred to me that the 351W is a 1969 vintage so maybe the whole drive train, rear differential and brakes have the same origin. No matter, the question will be the same - which brake drum to use.

Any thought, experience, wisdom on this?

Thanks :wall:
 

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don'k know if i can be of help but, redid the back brakes on my 65 last summer. being as the drums needed to be turned, badly, from scoring, decided to buy new drums. picked up a set from Advance Auto Parts, "Wearever" was brand, (don't know why? maybe cheaper than NPD? I live beside NPD) but anyways they looked great, and were much beffier than old ones. Problem now, :wall: the studs were to short to mount tires safely, back to Car Quest, there all right beside each other almost, for longer studs. next problem, :wall: needed to grind off slight amount of material,for the first stud would not sit flush, the ribbing that is on the stud to stop possible spinning was to much, after removing about 1/8 inch the rest went on perfect. job done. the new drums were not exact to old, why? who knows. but they worked, I'm happy. Next, front disks one day.
 

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Been awile since I have messed with the rear drums. There are 2 different drum sizes, 10 x 1 3/4 and 10 x 2. If I remember right the smaller drum was used on 65/6 coupes/fastbacks while the 2 inch was used on the convertible. Then in 67 all went to 2 in drums ??????
It sound like maybe you have the 1 3/4 inch drums, what width shoes are you running?? hopes this helps, Phil
 

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Discussion Starter #4
Phil, you may have a possible answer. The shoes on my FB are 1-3/4". I wonder if the drums on the car are 10x2 and the NPD replacements are 10x1 3/4. I'll know better once I've got it apart again today
 

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ALL 65/66 mustangs got the 10x1-3/4" rear drums(except shelbys) its quite possible that someone had replaced the correct drums with a 10x2" drum(but they actually should rub the backing plate) unless the whole rear was changed.
67-70 was a crapshoot, base V8(2V) cars would get the 1-3/4" while performance cars got the 10x2"(and some the 10x2.5")
so the answer is you ARE supposed to have 10x1-3/4" brakes(raised center area) but I can't answer why they look different.
 

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Discussion Starter #7
Just got in from garage. New NPD drums fit like a glove. Who knows why the difference but I'm not going back to try and figure it out.

Need to paint and install. What do you think about using 500 deg engine black on the drums?
 
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